Pressure pump



Feb. 27, 1945. A G GURRn-:s E1- AL 2,370,534

.PRES SURE PUMP Mraz/wi:

ATTYS Feb. 27, 1945.

A. G. GURRIES ET AL PRES SURE PUMP Filed Aug. 29, 1941 2 Sheets-Sheet 2 nl A f ,gf

Patented Feb.r27, 1945 I PRESSURE PUMP Albert G. Gurries and Thomas B. Keesling, Gilroy, Galli.; said Keesling assigner to said Gurries Application August 29, 1941, Serial IN1). 408,806

3 Claims.

This invention relates to pressure pumps, and particularly to one of the gear type, this pump being especially designed to supply oil or other 'uid medium at high pressure for use in the control of hydraulic mechanisms of various kinds, such as ground working and other equipment.

The principal object of our invention is to provide a pump of this general type so constructed that a very high pressure, up to 2000 pounds, or more, combined with a large volumetric capacity, may be created and so that wear between the gears and the cooperating side walls of the pump body is automatically taken up as it occurs within reasonable limits, so that the desired high pressure conditions may be maintained indenitely.

A further object is to construct a pump so that even though a very high pressure is present within the pump, ordinary packing glands are suiilcient to seal the projecting drive shaft of the pump against leakage.

The pump is adapted to be mounted on a tractor in front of the same, so that the pump shaft is directly alined with the engine shaft of the tractor.

A further object of the invention is to provide means, operable from in front of the pump, to enable the shafts to be releasably connected in driving relation, and to enable the engine shaft to be cranked, if necessary, either when the shafts are thus connected or when it is not desired to operate the pump and the latter remains disconnected from the engine after the latter is started.

A further object of the invention is to provide a simple and inexpensive device, and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects we accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several views:

Figure 1 is a sectional elevation of our improved pump.

Figure 2 is a front end elevation of the pump with the front end head half removed and showing said head partly in section.

Figure 3 is a transverse section of the pump casing on the line 3 3 of Fig. 1, with the gears removed.

Figure 4 is a fragmentary radial section of one of the end heads of the casing, taken on the line 4 6 of Fis. 3.

Referring now more particularly to the characters of reference on the drawings, the numeral i denotes the body of the pump casing, having an internal chamber 2 of a size to receive a pair of meshing gears 3 and d, the gear teeth having a close t with the periphery of the chamber, as usual. The gear t is mounted on a stub shaft 5 while the gear d is secured on a special drive shaft 6, which will be described in detail later.

Intake and discharge passages i and t respectively lead to and from the chamberv 2 on opposite sides centrally between the gears. The intake passage is divided adjacent the chamber into separate passages la, which face away from each other or in the direction of rotation of the gears (which is away from each other on the intake side, as is common practice), so that turbulence is eliminated and a more emcient lling of the spaces in the chamber between the gear teeth. is had.

The body, which is initially open at its ends, is recessed all about the chamber E as at 9 for the countersinking reception of relatively thin resilient wear plates Ill. These plates have bores II through which the shafts 5 and t project in clearance relation, the gears 3 and fi bearing closely or with a running fit against these plates.

The plates are held in place by rigid end headsv i2 bolted to the body, and which, together with the body, form the casing of the pump. The heads are formed with separated chambers I3 which communicate with the bores I I and which support the ball or similar bearings It for the shafts 5 and 6, the bearings being held clear of the plates I0. A passage I5.(see Fig. 2) connects the chambers of each head. The shaft 5 terminates within the heads, but the shaft 6 projects at both ends from the heads. Said heads are therefore provided with bosses I6 having bores I1 through which the shaft 6 projects with a predetermined close clearance, forming an orifice. The shaft is engaged by conventional packing glands I8 mounted in the outer end of the bosses.

Between the glands and-the chambers I3, annular grooves I9 are formed in the heads about the shaft 6 and which of course communicate with the orifices I1. .A passage 20 leads radially from each groove for a certain distance and then turns to extend lengthwise of the pump (see Fig. 4) to communicate with another passage ZI formed in the body I and leading to the intake passage 1 just behind the block or division member 22 which lies between and separates the passages la, as shown in Fig. 3. 4

In operation, it will be seen that -with the driving of the gears in the necessary direction and thedorcing of the liquid through thepump from the intake to thedischarge, pressure is built up in the chamber 2, (on the discharge side) forcing the plates l away from the ends of the gears 3 and 4' sufficient to allow some liquid to flow through this space and then through bores Il into chambers i3. This immediately builds up a pressure on the back sides of the plates I0 and since the back` side area of plates Il) exposed to the high pressure is greater than the area of the front side of the plates exposed to a correspondingly high pressure, the plates are again forced against the gears, and excessive leakage prevented.

By means of the pre-determined clearance of orifices Il, the liquid entering chambers I3 is bled o if, thereby preventing excessive pressure being built up in chambers I3, and which would result in unnecessary pressure of the plates l0 against the gears 3 and 4. As can readily be seen by those versed in the art, it is necessary to bleed off only a certain percentage of the liquid entering chambers i3, since should too much be allowed to pass at I1, suflicient pressure would not be built up to force plates lli against gears 3 and 4 and the leakage between the Plates and gears would soon become excessive, and high pressures could not be attained. The pressure holding the plates l0 against the gears is therefore always balanced with the pressure tending to force the plates away from the gears, so that wear is minimized and pressure leakage eliminated. This also allows for expansion of the gears due to heat, and wear of the plates, without reducing the running clearance. It also automatically compensates for wear within reasonable limits, as well as compensating forV any give or spring of the end heads and tie bolts, without affecting performance and,v

emciency.

A certain small percentage of the fluid such as oil, under high pressure in the chambers i3 passes through the orifices l1 about the close fitting shaft land enter the grooves I3, which in effect form oil retaining chambers. Since said grooves are connected by the passages and 2l with the. low pressure naturally present in the intake passage 1, the fluid in said grooves is constantly drawn into the pump and its pressure reduced instead of being forced further along the orifices l1 and into the packing glands, as would otherwise be the case. For this reason we are able to use conventional packing glands without having to set them up excessively tight. At the same time suilicient oil will pass to the glands to keep them lubricated.

The body at the intake projects well into the chamber 2 as shown. This not only enables the passages 1a to face more or less directly toward the gears, but provides additional support for the plates l0 at this point, or on the inlet' side of the pump. In this manner the high pressure bearing against the back side of the plates, as above described, does not force them against the gears and thus cause excessive wear, as ,would I otherwise be the case, due to the relatively low pressure in the corresponding portion of chamber 2.

When the pump is intended to be mounted on a tractor at the forward end of the same and with the shaft 6 in line with the crankshaft 23 23a of the shaft 23 (and which'y is in effect a clutch element) and cannot be used for this purpose when the pump is mounted, as above stated.

For'thls reason the shaft 6 is made special, as previously stated. Said shaft is tubular and slidable therein is an inner shaft 26. On its rear end said shaft 26 is secured by a diametral-pin-21 to a clutch collar 28 splined on the shaft 6. .'I'hls collar is initially clear of but is adapted to cooperate with the adjacent clutch member 23a in driving relationship. At its forward end, within the shaft 6, the shaft 2B is formed with an enlarged head 29 engaged by a helical spring 30 disposed about the shaft 26 behind the head and which acts to force the head forwardly and thus counteract and hold the collar 28 away from the element 23a. The outer end of the shaft 6 is formed with opposed notches or recesses 3l to receive the usual cross pin or similar element of a hand crank which when inserted in place, presses the head 29 back and shifts the collar into engagement with the element 23a. The shaft '5 is drilled, as at 32, to receive a crosspn 33 in position to hold the head 29 against retractlve movement when desired to maintain the engine and pump shafts in connected driving relation.

The engine may then be started by merely applying the hand crank to the outer end of the shaft 6, as will be evident. When, however, it is desired to start and operate the egine without running the pump, the pin 33 is removed. The

.collar 28 then only temporarily engages the element 23a when the handcrank is engaged with the shaft E and the head spring is advanced, since on removal of the hand crank the spring 30 acts to counteract the head and collar, leav.. ing the engine shaft free to rotate by itself.

From the foregoing description it will be readily seen that we have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a'. departure from the spirit of the invention, as dened by the appended claims.

Having thus described our invention what we claim as new and useful and desire to secure by Letters Patent is:

1. In a gear pump having a body provided with intake and discharge passages and pumping gears in the body, shafts on which the gears are mounted, an end head on the body having connecting chambers in which the shafts are journaled, one

-shaft projecting through the head from the corresponding chamber, a yieldable wear plate mounted between the head and body and separating the pump chamber from the head chamber; the plate having bores through which the shafts project and providing for a predetermined volumetric flow of fluid from the pump chamber to the head chambers, the head having an annular passage about the adjacent portion of said one shaft, said passage being in communication with the intake passage of the body and an orice being provided between said annular passage and the adjacent head chamber of smaller volumetric capacity than that provided by the' plate bores.

2. In a gear pump having a body forming a pump chamber and provided with intake and discharge passages and pumping gears in the chamber, shafts on which the gears are mounted, means to drive the shafts to operate the gears, an end head on the body, the shafts being journaled in such head, connected chambers formed in the head, and a yieldable wear plate mounted between the head and'body and separating the pump chamber from the head chambers; the plate having bores through which the shafts pro ject andsuch bores being of a size to provide for a predetermined volumetric flow of uid from the pump chamber to the head chambers, the head being provided within a relief passageway leading from the head chambersto the intake passage of the body, such relief passageway being of such a predetermined size as to provide for a 20 lesser volumetric flow of liquid therethrough than that provided by the plate bores.

3. In a gear pump having a body provided with a pump chamber and intake and discharge passages and pumping gears in the chamber, end heads on the body, resilient wear plates secured between the heads and body and capable of lateral deflection under pressure, fluid passage means provided between the pump chamber and the back sides of the plates, whereby, when the pump is operating, fluid under pressure will flow from the pump chamber to and against the backs of the wear plates to deflect and force said plates against the gears, and an internal block in the body between the gears on the intake side thereof only and which block engages adjacent portions of the wear plates to prevent inward de- -ection thereof at the intake.

ALBERT G. GURRIES.

THOMAS B. KEESLING. 

